Update AERIUS Calculator - New cut-off limit at 25km

The end of the year is once again approaching and with that it is traditionally time for a new update of AERIUS Calculator. With AERIUS Calculator, initiators, consultancies and governments can calculate the emission of nitrogen and its precipitation (deposition) on Natura 2000 areas. If that calculation shows that a particular development leads to an increase in nitrogen deposition on overburdened Natura 2000 areas, a permit under the Nature Conservation Act is usually required.

The annual update provides for incorporating the most current scientific insights into AERIUS Calculator. Apparently a lot of scientific insights have been gained this year because the upcoming changes are not minor. In this blog, we answer the question of what impact the changes will have in practice.

What is changing this year?
First, it is important to review the most relevant changes.

• The main change is the 25-km "cut-off limit" for nitrogen deposition for all projects. Any depositions beyond this cut-off limit will not be captured. This will have consequences especially for larger projects. Although the previous version of the AERIUS Calculator also included a cut-off limit, this only applied to road traffic and the distance was much shorter (5 km)

• In the new version, you can draw in buildings. This is useful for internal netting with buildings that were heated with gas in the old situation. In addition, drawing in buildings can make a difference in depositions at a short distance from Natura 2000 areas.

• New road traffic map layers are also becoming available. This makes it easier to visualize traffic flows and the associated speed limits.

• In addition, it becomes possible to calculate and compare up to six situations simultaneously. These different situations can then be referred to, for example, as 'the old situation', 'the balancing situation' and 'the intended situation'. Indeed, 5,000 different sources can now be entered instead of the initial 250 sources.

These last two changes to the AERIUS Calculator mainly improve usability.  

Where does the new cutoff limit come from?

The reason for the new cut-off limit is the final report of the advisory committee 'Measuring and calculating Nitrogen' (also known as the 'Hordijk Committee') and the decision of the Council of State about the A15 at the beginning of this year. This showed that the current of version of the AERIUS Calculator is not suitable for permit granting for several reasons:

• Different calculation models are wrongly used for, for example, a stable (the OPS model) or a road (the SRM-2 model). When calculating the nitrogen deposition for a road, a cut-off limit of 5 km was also used previously while no cut-off limit applied for other nitrogen sources. This difference was not explainable according to the Council of State.[1]

• The OPS model has been scientifically validated for individual sources for distances up to 20km.

On July 9, 2021, the Minister of LNV sent a letter to the chamber responding to these criticisms and announcing the new cut-off limit,[2]in which she also gives some additional reasons for the 25-km cut-off limit:

• the 25km limit is also used in permitting that involves air quality assessment. Nitrogen also plays a role in those regulations;
• Similar distance limits are used abroad;
• using a limit of 25km for all projects treats all nitrogen sources equally, making the calculation system more explainable.

What are the implications of the 25-km cutoff limit?

Article 2.1 of the Nature Conservation Regulations requires the use of the AERIUS Calculator version 2020 when assessing projects that may cause nitrogen deposition. When the new update of the AERIUS Calculator is released, the same article will be amended, making it mandatory to calculate with the new version.

Because the new version does not include (all) depositions above 25 km, they no longer need to be taken into account. This means that far fewer nitrogen effects are depicted in the new version. The great advantage of this is that there is also no longer any need to look for solutions in the form of external netting for small depositions that take place far from the project. This modified calculation method thus makes it easier to obtain a nature permit for larger projects in particular that involve relatively large nitrogen emissions. So to that extent (finally) good news for builders and developers!

At the same time, the cut-off limit for current initiatives can also turn sour. As a result, external offsetting is no longer possible with locations more than 25 km away from the Natura 2000 area on which your project causes nitrogen deposition. Certain, possibly already purchased nitrogen rights can in some cases suddenly no longer be used. In addition, the existing deposition banks will also temporarily not be usable after the release of this update until the cut-off limit is incorporated.

What happens to the pending proceedings?

The consultation version of the legislation implementing the update does not provide for transitional law,[3] meaning that in all pending applications where the application has not yet been decided on, new nitrogen calculations must in principle be provided. If a decision has already been made, the calculations do not necessarily have to be done all over again. It is established case law of the Council of State that a decision may be based on the version of the AERIUS Calculator available at that time,[4] but for the legal tenability of a decision in an ongoing appeal procedure it is advisable to also make a calculation with the new version. Because of the cut-off limit of 25 km, in many cases a recalculation will lead to a more favorable result. Also, drawing in buildings as yet, which can be done after the update, can make a difference in depositions at short distances."[5]

Conclusion

When the latest update of the AERIUS Calculator is implemented, the cut-off limit of 25 km will make it easier to get a nature permit for the larger projects in the future. There are even areas in the Netherlands (such as Eemshaven) that are more than 25 km from a nitrogen-sensitive Natura 2000 site. With the new AERIUS Calculator, nitrogen depositions can no longer be calculated for these areas. At the same time, it should be emphasized that this new version has not yet been submitted to a judge and nature organizations have already announced that they will litigate against this new calculation method .

[1] ABRvS January 20, 2021, ECLI:NL:RVS:2021:105, r.o. 69.5.

[2] Appendix to Parliamentary Papers II 2020/21, 35334, no. 158.

[3] https://www.internetconsultatie.nl/rnb_stikstof

[4] ABRvS 4 August 2021, ECLI:NL:RVS:2021:1760, r.o. 11.2, ABRvS 22 April 2020, ECLI:NL:RVS:2020:1110, r.o. 12.11.

[5] ABRvS May 29, 2019, ECLI:NL:RVS:2019:1603 r.o. 39.3.